The invention relates to the automatic doffing of a strand package which has been formed on a rotating collet and the like wherein a full strand package is doffed from the collet while rotating.
In the manufacture of wound strand packages in which a continuous strand of fibers is advanced to a rotating collet to form a strand package thereon, the problem occurs of removing the strand package once it has become full, while not interfering with the continuous strand-forming process. In the production of synthetic strands, the individual fibers comprising the strand come from an extrusion machine or furnace in which the multiple filaments are extruded continuously through spinneretts or bushings. The process is continuous, and the winding of the filaments in the form of a single strand to form a package cannot occur intermittently without the production of waste or inferior quality strands. In particular, fiberglass production requires continuous furnace operation and winding at higher speeds than other synthetics resulting in more waste during doffing of full packages and starting of new packages.
Heretofore, numerous techniques have been utilized for moving a full package of a continuous strand wound upon a tube or other carrier, ranging from manual doffing to automatic mechanical doffing. Automatic doffing devices are disclosed in U.S. Pat. Nos. 3,908,918 and 4,138,072. These patents disclose means for ejecting the full strand package from the winder by utilizing some mechanical means for pushing the package off of a spindle while in a stationary position.
It is also been known to utilize a pneumatic gripper for doffing a bobbin from a spindle overhead when stationary such as shown in U.S. Pat. Nos. 4,472,934 and 2,952,113. While these devices disclose the use of a pneumatic gripper, the methods and apparatus are suitable only for doffing a stationary package from a stationary doffer in a very limited motion.
It has also been known in the manufacture of continuous strands of glass fibers to utilize turret winders so that the continuous production of the strand is not interrupted when stopping the winder to doff the strand package. However, utilization of the turret type winder complicates the strand production process considerably owing to the more complex and space consuming nature of the turret winder.
Accordingly, an important object of the present invention is to provide a method for automatically doffing a strand package formed on a draw type winder having a rotating collet upon which the strand package is formed without interrupting the rotation of the winder nor the continuous production of the strand.
Still another important object of the present invention is to provide a method for automatically doffing a strand package formed on a collet of a draw type winder without interrupting the rotation of the collet and the strand production process.
Still another important object of the present invention is to provide a method for automatically doffing a strand package formed from a single continuous strand while the package is rotating.
Yet another important object of the present invention is to provide a method for automatically doffing a rotating strand package formed on a rotating collet of a collet winder wherein a rotating doffing cup is utilized to grip the rotating strand package and retract it from the rotating collet without interrupting the winding operation of the collet and continuous production of the strand.
Yet another important object of the present invention is to provide a method for automatically doffing a rotating strand package wherein a rotating doffing cup is utilized to grip the strand package while it is rotating and remove it from a rotating collet in a manner that automatically causes a trailing strand to be wound upon the empty collet to start the winding of a new strand package, all the while the winding operation of the collet and the production of the strand are continued.